The present invention relates to a security system for selectively enabling or inhibiting operation of a document processing apparatus such as a copier or facsimile transmission apparatus.
In general, security systems for controlling copying of documents are known. For example, various systems have been proposed wherein confidential documents are printed on paper having particular physical characteristics and/or with ink having particular characteristics that prevents the copier apparatus from perceiving the printed matter. Examples of such systems are described in U.S. Pats. No. 4,118,122 issued to Rees et al on Oct. 3, 1978; 4,025,673 issued to Reinnagel on May 24, 1977; 3,852,088 issued to Godlewski et al issued on Dec. 3, 1974; 3,831,007 issued to Braun on Aug. 20, 1974; and 3,807,852 issued to Hoydic issued on Apr. 30, 1974. Other such systems are described in Hildenbrandt "Document Security for Copiers" IBM Technical Disclosure Bulletin Volume 19 No. 9, February 1977; Bruce, "Document Copy Prevention" IBM Technical Bulletin Volume 18 No. 1, June 1975; and Weinberg "Document Copying Inhibitor Method" IBM Technical Disclosure Bulletin Volume 17, No. 12, May 1975.
Other systems detect particular characteristics of the paper or ink or preprinted indicia on paper to identify confidential documents and inhibit copier operation. Examples of such systems are described in Boggs et al, "Copier Incorporating Document Detection System," IBM Technical Disclosure Bulletin Volume 15, No. 7 December 1972; Harr et al, "`No-Copy` Attachment for Copier" IBM Technical Disclosure Bulletin Volume 17 No. 11 April 1975; Simpson, "Copier Document Security" IBM Technical Disclosure Bulletin Volume 17 No. 11, April 1975; Galli et al, "Copier Security System," IBM Technical Disclosure Bulletin Volume 18 No. 3, August 1975; Queener, "Document Copy Prevention" IBM Technical Disclosure Bulletin, Volume 18 No. 6 November 1975; Bruce, "Unauthorized Copy Prevention", IBM Technical Disclosure Bulletin Volume 18 No. 1, June 1975; Guido, "Preventing Copying of Classified Information" IBM Technical Disclosure Bulletin Volume 19 No. 4, September 1976; U.S. Pat. No. 3,597,082 issued to James et al on Aug. 3, 1971; and U.S. Pat. No. 3,977,785 issued to Harris on Aug. 31, 1976.
For example, Guido describes a system wherein preprinted bar-codes are detected by a scanner and compared by a microprocessor to classification ratings and passwords maintained in a read only memory. The person operating the copier is then required to enter a password before copying of a confidential document can be effected.
The Harris patent describes a system where preprinted coded information on a document is optically correlated with a reference pattern, to inhibit operation of the copying machine in the absence of proper correlation.
Other systems utilize a metallic or conductive tag or a conductive paper to prevent copying of secured information. Examples of such systems are described in Boggs et al, "Unauthorized Copy Prevention" IBM Technical Disclosure Bulletin Volume 15 No. 12, May 1973; Boggs et al "Gradiometer Document Detector for Copy Security" IBM Technical Disclosure Bulletin Volume 16 No. 6, November 1983; Bacon, "Secure Document Feature for Copy Machines" IBM Technical Disclosure Bulletin Volume 17 No. 11, 1975; and Bacon et al "Secure Document Feature for Copy Machines" IBM Technical Disclosure Bulletin Volume 18 No. 4, September 1975.
Other systems, such as described in Marinace, "Copier System for Confidential Papers" IBM Technical Disclosure Bulletin Volume 15 No. 7, December 1972 requires that indicia of user identification be provided the copying machine before the machine will operate.
Security systems for facsimile transmission apparatus are also, in general, known. An example of such a system is described in U.S. Pat. No. 3,261,911 issued to Bailey et al Jul. 19, 1966. Security systems for use in a computer system having remote terminals are also known. See, e.g. U.S. Pat. No. 3,984,637 issued on Oct. 5, 1976 to Caudill et al.
The prior art systems tend to be disadvantageous in that they require that secured documents be printed on specially treated paper stock having predetermined characteristics, or with particular ink, or on paper bearing preprinted visual indicia, e.g. particular patterns or bar-codes, that tend to be subject to masking by an unauthorized user.